Short circuting USB port?

[Richard A. Smith]

James Cameron wrote:

> 1.  a battery that is faulty,

Very likely.  See:

http://wiki.laptop.org/go/XO_LiFePO4_Recovery_Procedure

For diagnostic and repair.

> 3.  a USB device that is faulty, in that it draws more current than it
> ought to do,

The ports are limited to a max of 1A summed across all ports.  I've 
tested this repeatedly.  I often put a 5 ohm load on the usb power lines 
to discharge batteries faster.  A sudden 1A draw would cause a bit of a 
dip on the battery voltage so if the battery is already really low this 
might be the cause.

> The support team has a battery charge monitoring script, if I recall
> correctly.

'olpc-pwr-log' Its in all new builds See here:

http://wiki.laptop.org/go/LX_Power_Measurements#olpc-pwr-log

-- 
Richard Smith  <richard at laptop.org>
One Laptop Per Child